It is a phenomenal accomplishment that the vaccine gained approval for use from the UK government on 30 December 2020 when Oxford University only started to develop the vaccine in February 2020, and phase I clinical trials of the vaccine commenced in April 2020.
How does it work?
According to Wikipedia "the AZD1222 vaccine is a replication-deficient simian adenovirus vector, containing the full‐length codon‐optimised coding sequence of SARS-CoV-2 spike protein along with a tissue plasminogen activator (tPA) leader sequence". What does this actually mean? Oxford University took a modified chimpanzee virus (which causes the cold in chimpanzees and is harmless to humans), and added the genetic code for the COVID-19 virus spike protein. This genetic code is optimised for human cells to express the spike protein. The spike protein is found on the surface of the COVID 19 virus, making it a good target for the human immune response. When the vaccine enters cells inside the human body, the cell "machinery" uses the genetic code of the vaccine to produce the spike protein of the coronavirus. An immune response is then induced, priming the immune system to attack the coronavirus if it later infects the body.
Of course we are concerned about mutations in the COVID-19 virus, especially mutations in the spike protein which might make the AZD1222 vaccine less effective. However the AZD1222 vaccine can be adapted to target new variants of the COVID-19 virus spike protein. The adapted vaccine can be administered as a "booster".
Results from the first study to describe the effectiveness of the AZD1222 vaccine, conducted by researchers from universities across Scotland and Public Health Scotland, have suggested that the vaccine is able to substantially reduce the risk of COVID-19 related hospitalisation by 94% after the first dose. These findings were based on data from 1.14 million COVID-19 vaccinations administered in Scotland, UK with approximately 490,000 people having received the first dose of the AZD1222 vaccine. The study has not as yet been peer-reviewed, but the results seem promising.
Why UK regulatory approval was granted so quickly
In a bid to speed up its approval of the AZD1222 vaccine, scientists from the UK Medicines and Healthcare products Regulatory Authority (MHRA) began examining trial data in October, the agency said, in a process called a “rolling review", where packages of data from ongoing clinical trials are made available as soon as they’re ready, rather than at the end of the trial. This approach helps fast-track analyses of potential drugs or vaccines during a public health emergency.
An accomplishment for British science
On 30 December 2020, Professor Louise Richardson, Vice-Chancellor at the University of Oxford, said: “This is a great day for British science and a great day for universities everywhere. Above all, it is a great day for the many people whose lives will be saved by this vaccine".
A key element of Oxford’s partnership with AstraZeneca is the joint commitment to provide the vaccine on a not-for-profit basis for the duration of the pandemic across the world, and in perpetuity to low and middle-income countries.
It can take years to find a vaccine for a disease and gain approval for use, and so the world-class team of scientists at Oxford’s Jenner Institute are to be congratulated on an extraordinary achievement. This really is a story of British scientific excellence.